Question

The electric force between a charged foam cup and a positively charged metal sphere is 2.12 newtons. If the charge on the cup is 2.0 × 10-6 coulombs and the charge on the metal sphere is 2.5 × 10-6 coulombs, what is the distance between the two? (k = 9.0 × 109 newton·meter2/coulombs2) i know the formula but dont know how to use it :(

Answer 1

Hint, Coulombs Law states \(\large F = k\frac{|q_1||q_2|}{r^2}\)

Where F is the force between the 2 objects (given)

Soo we can pug everything we have in

\[\large 2.12N = (9.0\times 10^9 \frac{Nm^2}{C^2})(\frac{|2.0 \times 10^{-6}C||2.5\times 10^{-6}C|}{r^2})\]

So notice that we just want to solve for the distance between the 2...hence we just solve for 'r'

\[\large r = \sqrt{\frac{ (9.0\times 10^9 \frac{Nm^2}{C^2})|2.0 \times 10^{-6}C||2.5\times 10^{-6}C|}{2.12N}} = ?\]